It is often desirable to know the location of a mobile device such as a cellular phone. For example, a location services (LCS) client may desire to know the location of a mobile device in the case of an emergency services call or to provide some service to the user of the mobile device such as navigation assistance or direction finding. The terms “location” and “position” are synonymous and are used interchangeably herein. One method of determining the location of mobile device is based on measurements of the times of signal arrival from multiple antennas. For example, a mobile device may measure time differences in received signals from a plurality of base station antennas. Because positions of the base station antennas are known, the observed time differences may be used to calculate the location of the mobile device. An mobile device may make use of a Base Station Almanac (BSA) to perform measurement calculations and/or may send the measurements to a location server for position calculation. The term Advanced Forward Link Trilateration (AFLT) is used to describe terrestrial positioning in Code Division Multiple Access (CDMA) systems, while the term Observed Time Difference of Arrival (OTDOA) is used in the context of Wideband CDMA (WCDMA) and Long Term Evolution (LTE) systems. The accuracy in terrestrial positioning is dependent on synchronization of base station clocks and signal transmissions. Variations in hardware and installation procedures may cause a time bias for a cell signal and decrease the accuracy the positioning estimate.